Used Outboard / Even Compression

[O.T.Water]

So I've been reading alot of threads and am confused. I'm considering a repower in the 90hp range and I see lots of information pointing in all directions. But one hits me and that is even compression is the biggest factor when selecting a used unit. But one question I have is, How far should the existing even compression ratio be from the compression ratio when the engine was new? 10, 20, 30lbs? Certainly there must be a figure to go by in case it's been taken care of but is just worn out! Input appreciated. O.T.

 

[crb478]

Re: Used Outboard / Even Compression

Most gauges read different, but consistant. If the cylinders are within 10 percent of each other that is usually considered good. Ideally you would like them all over 100 psi and within 10 percent of each other, but with two different guages one may read 90 while the other reads 110.

 

[JB]

Re: Used Outboard / Even Compression

The single most important thing is a successful on-the-water demonstration.

Compression testing is, at best, a diagnostic looking for a sick cylinder.